From the strict rectangles of structured data to the more generous triangles of semistructured data. This morning’s lecture gave an overview of what kind of data is seen as “semistructured”; the idea of trees as a mathematical model of data; the particular form of trees in the XPath data model; and their textual representation in XML — the Extensible Markup Language.

XML also has a large number of domain-specific variants. These are all valid XML, and use standardised sets of element types to give a custom language for representing data relevant to a particular field: from musical scores to financial trading.

Links: Slides for Lecture 9; Recording

Homework

1. Read This

• XML Essentials from the World Wide Web Consortium (W3C).

  Link: XML Essentials — What is XML? What is XML used for?

• Sections 2.1–2.5 from Chapter 2 of Møller and Schwartzbach. I have sent a scanned PDF of this chapter to all students by email; there will also be printed copies outside the ITO in Forrest Hill; and you can find the whole book in the Library HUB.

2. Do This

• Find an SVG file and open it in a text editor to study its XML content.

• Find a Microsoft Office .docx file and look at the XML content in that. This format (OOXML) is in fact a zipped archive of XML files, so you will need to unzip it first. Depending on your platform, this may require renaming the .docx extension as .zip

  Link: Wikipedia on Microsoft’s OOXML format

References

To learn more about XML, try any of the following.

• Read more of An Introduction to XML and Web Technologies, the book in today’s homework reading. There are copies available right now in the Main Library HUB.

• Work through the MusicXML tutorial.

• Browse the full XML specification.

• Have at look at some documents in the Financial Products Markup Language: such as a composite basket equity swap or a European swaption straddle. The full site has dozens of such examples.

Original Research Inside the Database

	Discovery of Peculiar Periodic Spectral Modulations in a Small Fraction of Solar-type Stars Ermanno F. Borra and Eric Trottier Publications of the Astronomical Society of the Pacific, Volume 128, Number 969, November 2016. “… generated by extraterrestrial intelligence.” Link: Paper
	Strange messages coming from the stars are ‘probably’ from aliens, scientists say The Independent Andrew Griffin, Monday 24 October 2016 Link: Article